I have written a lot about Indiana recently. Mostly because I live here now and think of it as home, although I have lived here fewer than half of the years of my life.
I was born in OH and lived there my first four years. Not long after we had moved to Indianapolis, my mother suggested one day, for no apparent reason, that I should “act like a human.” By that time I had heard Indiana folks referred to as Hoosiers. Getting only slightly confused by the two “H” words, I retorted, “I’m not a human; I’m a Buckeye.”
Since then, though, I have thought of myself as a Hoosier, doubly so, as one who calls Indiana home, and one who graduated from Indiana University.
Not long before Christmas, I saw an ad for a book called Undeniably Indiana, an IU Press publication celebrating the 2016 state bicentennial. A few of the authors were listed in the ad. Among them was John Robert McFarland. At first I thought there had to be another such character. Then I remembered that short articles had been solicited for the chapter on why Hoosiers are called Hoosiers. I knew the answer so I wrote it up, and then forgot about it, a skill at which I am getting better and better as I age.
So I asked for a copy of the book for Christmas. Daughter Mary Beth obliged. Here is my contribution, in full, at the bottom of page 13:
“Indiana is the only state named for a Methodist circuit rider, Black Harry Hoosier.”
Actually I wrote two or three paragraphs, but the editors boiled my contribution down to that one sentence. That’s what good editors do. 
“Black Harry” was born in 1750 and died in 1806. Indiana became a state in 1816. In the middle and late 1700s, he was an eloquent traveling evangelist, especially popular with the pioneers in the new not-yet-state of Indiana. Many said that despite his lack of education, he was American’s foremost orator. One of his sermons, “The Fig Tree,” was the first American sermon to be recorded. [written down by others]
Because the Indiana pioneers responded so well to his preaching, they became known as "Hoosiers."
It is fascinating, considering Indiana’s long history of virulent racism, that its citizens are called by the name of a black man.
You can find a much more detailed, but very readable, article about Indiana’s name sake, by Stephen H. Webb, in the March 2002 edition of Indiana Magazine of History, published by Indiana University. Just fire up the Google machine and type in “Black Harry Hoosier.”
1] Editors always want articles to be shorter, especially if they are paying by the word. I have a recurring dream in which I have finally honed my article down to one word, to which my editor replies, “But can’t you find a shorter word?”